The Japanese patent application Kokai No. 63990/1976 discloses the manufacture of 1.alpha.,17.beta.-dihydroxy-steroids by 1.alpha.-hydroxylation of 17.beta.-hydroxy-17.alpha.-substituted or unsubstituted 4-oestren-3-ones by means of microorganisms of the genus Rhizoctonia, Calonectria, Glomerella, Aspergillus, Corticium, Septomyxa, Mucor, Isaria, Irpex or Fusarium. All of these organisms, with the exception of the species Aspergillus terreus, are not in the position to hydroxylate dehydroepiandrosterone in the 1.alpha.-position. This fact means that a 1.alpha.-hydroxylation of steroids can be carried out only with quite specific combinations of microorganisms and substrates. It is, indeed, very difficult to discover such a combination. According to the process of the above-mentioned patent application, Aspergillus clavatus ATCC 9598, A. fumigatus mut. helvola CBS 110.46 and A. conicus IFO 4047 are microorganisms which can hydroxylate in the 1.alpha.-position steroids with an oxo group in the 3-position, a double-bond in the 4,5-position and a hydroxy group in the 17.beta.-position. These aforementioned microorganisms can not, however, hydroxylate in the 1.alpha.-position dehydroepiandrosterone or derivatives thereof which have in the 3-position a hydroxy group, 5,6-double bond and a 17-oxo group.
U.S. Pat. No. 2,882,794 discloses a process for the hydroxylation of dehydroisoandrosterone (dehydroepiandrosterone) in the 1.alpha.-position by means of Penicillium sp. ATCC 12556. This process has the disadvantage that substrate concentrations, namely 0.35 g/l, must be employed. It is difficult to manufacture 1.alpha.-hydroxy-dehydroepiandrosterone in high yield according to the procedure described in the above U.S. Patent. Furthermore when low substrate concentrations are used the hydroxylation product appears to decompose immediately after reaching the highest yield.